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If the PCB has several "causes" such as SGND, AGND, GND, etc., the main "ground" in the jet PCB board is recorded separately according to the position of the board. That is the connection. At the same time the earth.
There are several reasons for the widespread use of copper.
1) EMC. For a large area of land or air supply, there are shielding, and some special areas, such as PGND protection.
2) PCB-Required process. The copper fuse PCB is located on the floor, and the wiring is small to avoid the influence of electroplating and lamination deformation.
3) Requires a mark of integrity. This route provides a complete journey of high-frequency digital signals and reduces the wiring in the DC network. Of course, there are also reasons for loss of air heat and installation of special equipment. Bronze layers usually have multiple reasons.
a. EMC. For a large area of land or air supply, there are shielding, and some special areas, such as PGND protection.
b. Requires PCB processor. The copper fuse PCB is located on the floor, and the wiring is small to avoid the influence of electroplating and lamination deformation.
c. The signal integrity requirements provide a complete return path for high-frequency digital signals and reduce the wiring of the DC network. Of course, there are also reasons such as heat dissipation, special device installation requires copper and so on.
1. One of the main advantages of copper pavement is to reduce soil resistance (many so-called antifouling agents are also due to the reduction of soil resistance). Since digital circuits contain a large amount of spike current, it is necessary to further reduce the ground impedance. It is generally believed that circuits containing digital devices need to have a larger ground area. In the case of analog circuits, a ground loop formed by copper coating will cause electromagnetic coupling. Interference that exceeds the gain (excluding high-frequency circuits). Therefore, not all circuits need ordinary copper (by the way: copper mesh has better shielding performance than the entire block).
2. The importance of the copper circuit in the circuit is reflected in the following places: 1. Since the copper path is connected to the ground wire, the loop area can be reduced. 2. Spreading a large area of copper is equivalent to reducing the resistance of the ground wire and reducing the voltage drop between these two points. That is to say, whether it is digital ground or analog ground, copper needs to be added to enhance the anti-interference ability, and at high frequencies, it is necessary to separate the digital ground from the analog ground, spread the copper, and then connect them to one point. .. Before connecting, this single point can be wound around the magnetic ring several times with a wire. However, if the frequency is not too high, or the equipment is in good working condition, it can be very calm. The crystal oscillator can be counted as a high-frequency radiation source in the circuit, scatters copper, and then polishes the crystal oscillator housing.
3. What is the difference between a copper block and a grid? Detailed analysis has three functions. 1 Beautiful 2 Anti-noise 3 Reduce high-frequency interference according to wiring standards (the reason for the circuit board): Why should the power supply and ground layer be as wide as possible? Want to add a grid? Oh, isn't this in accordance with the principle? When it comes to high frequencies, it is even more wrong. If high-frequency wiring is taboo, then sharp effects are also taboo. If the power plane exceeds 90 degrees, many problems will occur. Actually, why is the whole process needed? Check if the type of hand-painted solder is therefore almost inconsistent. If you see a picture like this, it must be gone. At the time, the reason was a technique for installing wave soldering. He had to heat the table locally. Of course, if the heat transfer coefficient is different, all the copper is scattered, the board will rise, and the board will have problems when it rises. The tip pin is on the top steel cover (this also requires a process). It's easy to make mistakes, and the rate of brushing continues to rise. In fact, this method has its drawbacks. The current etching process makes the film easy to adhere. In the later strong acid project, the points may not be corroded and there are many residues.But if the board is broken, the chips on it will be eaten up with the board! Do you know why you need to draw from this angle? Of course, some surface devices are not classified. There are two possible scenarios in terms of product consistency. 1.The corrosion process is very good. 2.Do not use wave soldering, instead use reflow soldering, but in this case the overall investment of the assembly line will be 3-5 times higher.
